B-SIM V2.5 Reference - Blow molding simulation
Post-processing is used to explore the final simulation results, calculate part cooling, distort and pre-distort images etc.
Opening a solved project for post-processing
There are several ways how to open a project for post-processing:
Available optimization modules
Refinement from post-processing
Manual refinement 2:
Pre-stretched parison can be save as B-SIM grid (BCS file type) using command Grid / Save deformed grid as BCS. The resulting file can be used in a new project as the pre-stretched parison. Regarding pre-stretching, see Process control description.
The sub-menu Grid / Export for structural analysis enables to export
thermoformed product geometry, thickness and temperature to several
formats ( DXF, IGES, Patran, Cosmos / M). The exported files can be
used for structural analysis.
DXF Out creates a text file consisting of Autocad entities called 3DFACE. Such a DXF file can be used in Autocad or other CAD packages to visualize post-processing results. The file exported does not contain any information about thickness or temperature.
IGES Out creates a text file consisting of two spline surfaces. The first surface describes upper part of the product, second spline surface gives the lower part. Distance between these two surfaces is given by thickness of a thermoformed product. Such an IGES file can be used for consecutive post-processing with other CAD packages, mainly for static analysis of blow molded product. Starting from B-SIM Version 2.5, the optimized 3D preform geometry can be exported to IGES for a direct import to 3D CAD.
Cosmos/M Out creates a file directly readable by COSMOS / M structural analysis program. The file exported contains only thickness information. Temperatures are not exported.
Patran Out creates five files - *.out, *.nod, *.tep, *.elm and *.fin in PATRAN format.
Map to LS-Dyna creates an LS-Dyna file based on a "template file" (LS-Dyna file without thickness information). The new LS-Dyna file contains the same information as the "template file" with nodal thickness values added. Projected and original LS-Dyna nodes are displayed once the mapping process is finished. The original nodes are in white and the projected nodes are in pink color.
Starting with B-SIM V2.31, calculation of weight of selected areas of deformed grid (parison / preform) is possible. This feature offers much more straightforward way to analyze the final product properties than the old Trim line feature. A short example how to use this feature can be found here.
Having a solved project open for post-processing, use the toolbar on the left side of the post-processing window to select element to be included in weight calculation.
How to select elements:
Having elements selected, click on Grid / Properties in post-processing menu. The following window appears with details about selected area:
This window is modeless, this means you still can continue in elements selection / unselection. Imformation about volume and weight is updated automatically.
The following commands are accessible from Grid / Trim line menu:
The loaded trim line is superposed onto the preform / parison and the mass of the selected part of the sheet is calculated.
Format of Trim Line file (*.CDL):
Then the points representing the trim line are created. Now go to FILE menu and click CADL. Then select WRITE. Enter a filename to save the data. Remark: When exporting to CADL, only the layer containing the set of points representing the trim line should be active.
In B-SIM: Open a solved project in post-processing. Select command Load trim line from Grid / Trim line menu. Enter the name of the CADL file previously created in SurfCam. The trim line is loaded and volume etc. of the selected part is calculated.
Format of CADL file containing Trim Line data:
(Resulting Trim Line)
When in post processing, use command Cooling / Calculate cooling (located on Post processing toolbar) to calculate the blow molded part cooling.
Remark: The cooling calculation is possible only when the project was
completely solved using B-SIM Version 2.1 or later.
Use the Make cut button to make a cut on the deformed preform / parison. Making a cut:
Once the cut is created, the correspondence between the 2D cut graph and the original 3D picture can be easily found when placing the mouse cursor to the area of 2D curve of thickness(temperature, stress or extension) / arc length. After pressing and keeping pressed the left mouse button, the vertical line appears on the graph and the double lined cross in the 3D picture. When moving the cursor, the cross moves in the 3D space, thus giving a track of a desired position both in 2D and 3D. The window with the graph can be moved or resized so that it does not hide the area of interest in the 3D picture. To modify the graph limits, click on Limits. Use the [T] button to force the cut window to remain on the top. When the button is pressed, the cut window remain on the top. It is possible to print out the cut graph - use Print command from Cut menu.
3D cut data table
This dialog contains data of a cut created from 3D cut view. In Distance between cut points specify a positive value in mm / inch and press Enter key or click on Regenerate cut points. Cut points will be recalculated. To include 3D coordinates of the cut points into the cut data, check Include 3D cut points coords. Click on Copy to clipboard to copy the cut data into clipboard. These data stored in clipboard can be used for transfer into MS Excel etc. Click Close to close the dialog.
Display / Export / Video
Display / Export / Bitmap
Display / Export / VRML
Display / Export / HTML (VRML+scale)
The created HTML file can be opened in any HTML browser. A 3D VRML viewer plug-in has to be installed in order to display the VRML model on HTML page. On this page, a list of VRML viewers is available. Accuform recommends the following VRML viewers: CosmoPlayer and WorldView.
It gives information about the files used in project, job number, number
It gives information about the active record number, inflated grid
outer box dimensions, the time of the process until the active record,
the pressure achieved and the inflated volume. The average thickness
value is calculated from the grid elements which are not clamped.
Thickness non-uniformity factor:
deformed preform/parison area
With a B-SIM project open for post processing, click on Grid / Properties to display the following information box:
It gives information about the number of elements (triangles), the dimensions of the deformed grid, mean thickness (for the whole grid and for the grid excluding clamped elements) and mean temperature.
B-SIM is capable to automatically optimize the initial parison / preform thickness in order to get uniform thickness distribution on a final product. First, open a solved project for post-processing. Now, select the command Optimizations / Optimize thickness. B-SIM creates a new subdirectory "OptimThickness" and in this directory, new optimization projects are automatically generated. Once B-SIM is prepared to start the optimization, the following message box appears together with the optimization batch view:
Now click OK to start the optimization batch solution. Another message box asking for confirmation appears. Click Yes and the optimization will start. Ten optimization projects will be solved to get the optimized initial parison / preform thickness profile. Please wait until the optimization batch is solved. This can take a long time, especially in case the solution of the initial project took hours. Once the optimization is finished:
The optimized preform (injection blow molding process) can be exported to IGES for further CAD work (Injection molding mold desing).
B-SIM is capable to automatically optimize the initial preform temperature in order to get uniform thickness distribution on a final product. First, open a solved project for post-processing. Now, select the command Optimizations / Optimize temperature. B-SIM creates a new subdirectory "OptimTemperature" and in this directory, new optimization projects are automatically generated.
Click OK to start the optimization batch solution. Another message box asking for confirmation appears. Click Yes and the optimization will start. Ten optimization projects will be solved to get the optimized initial preform temperature profile. Please wait until the optimization batch is solved. This can take a long time, especially in case the solution of the initial project took hours. Once the optimization is finished:
B-SIM is capable to automatically optimize the initial preform length in order to get uniform thickness distribution on a final product. First, open a solved project for post-processing. Now, select the command Optimizations / Optimize preform (L/D). The following dialog appears:
Enter minimum and maximum for the preform length and number of optimization points. in this case, 5 projects are created, with preform having length 100, 110, 120, 130 and 140 mm. Click OK.
B-SIM creates a new subdirectory "OptimPreformLD" and in this directory, new optimization projects are automatically generated.
Click OK again to start the optimization batch solution. Another message box asking for confirmation appears. Click Yes and the optimization will start. Please wait until the optimization batch is solved. This can take a long time, especially in case the solution of the initial project took hours. (Estimated optimization time was displayed in Preform optimization options dialog.)
Once the optimization is finished, B-SIM displays a message about the result. in B-SIM Messages bar, there is a detailed info about the final thickness distribution for all the simulated projects:
To analyze critical venting areas, open a B-SIM project for post processing, click on Project / Critical venting areas. The analysis starts immediately. When it is finished, every element has one of the following colors:
Red color: The area is not on mold wall
Yellow color: The area is just touching mold wall
Blue color:: The area lays on mold wall
To analyze how the mold is filling and what areas have a critical venting condition, explore different simulation records. To terminate the critical venting areas analysis, click on Project / Critical venting areas.
Having a solved project open for post-processing, use the toolbar on the left side of the post-processing window to select elements and to modify the boundary conditions on their nodes.
First, select the elements for modification (details about elements selection can be found in the section about Part weight calculation). Having elements selected, any of the following actions can be performed:
Add "no pressure" flag
Remove"no pressure" flag
Clicking on button associated with one of the actions described about immediatelly add/remove clamping/"no pressure" flags to/from the selected elements.
When in post-processing, Analyze / Element history command enables advanced analysis of deformation, stress and temperature history of selected element(s).
Having a solved project open for post-processing, use the toolbar on the left side of the post-processing window to select at least one element. Now click Analyze / Element history.
Element history data are automatically copied to Clipboard. Use Copy/Paste command to put the data into your favourite spreadsheet software to create graphs showing dependency of deformation on time, stress on time, stress on deformaiton etc.